Multiple-spark discharge occurring between a charged conductive plate and a grounded sphere electrode

The characteristics of the spark discharge occurring between the conductive square plate charged by induction charging and the grounded sphere electrode have been investigated experimentally for various plate sizes and charging voltages. The spark discharge with multiple-peaks in the current waveform was observed only when the plate was positively charged. The multiple spark with peaks more than three occurred irregularly for a plate larger than 0.4 m in side length at the charging voltage lower than 10 kV. The double spark discharge was reproducible for the plate larger than 0.3 m at the higher charging voltages. The double spark discharge would be caused by the incomplete first spark with relatively less conductive spark channel.